package joboo4;

public class job04 {
    public static void main(String[] args) {
        StringBuilder builder1=new StringBuilder();
        StringBuilder builder2=new StringBuilder();


        String str="abc";
        StringBuilder builder3=new  StringBuilder(str);
        String str2=builder3.toString();

        String a="好好学习";
        StringBuilder builder=new StringBuilder(a);

        builder.append(",天天向上");
        System.out.println(builder);

        builder.replace(5,9,"积极进取");
        System.out.println(builder);

        builder.delete(5,9);
        System.out.println(builder);

        builder.insert(5,"天天向上");
        System.out.println(builder);
    }
}
